Rolling mills for rolling steel bars are known in the art, which downstream the last rolling stand shearing means are provided in order to shear the rolled material to a length which is a multiple of the commercial length, and is generally comprised within the range of from 40 to 100 meters.
Therefore in a traditional rolling mill--whether of the type in which a natural air cooling is provided for the rolled material, or in which a forced on-line cooling is provided--downstream of the last rolling stand a shear is positioned, which performs the task of shearing the bar to a length which is a multiple of the commercial length. Downstream of said shear a feed table is provided, which feeds the sheared bars to a cooling bed having such a length as to enable the sheared bar material to be braked by exploiting the natural friction of the same material with the plane along which it slides; said length is generally comprised within the range of from 35 to 60 meters, as a function of the maximum rolling speed.
Downstream of the feed table, the cooling bed is installed, which has a length comprised, as said, within the range of from 40 to 100 meters, and a width of from 8 to 12 meters.
When they leave the cooling bed, the bars are fed through a roller apron to a shear wherein the simultaneous shearing takes place of a plurality of cold bars to commercial length (said length is generally comprised within the range of from 8 to 24 meters).
Then apparatuses follow, which perform the tasks of forming the bundles, tying and subsequently discharging said end bar bundles to the material storage.
This type of facility suffers from the drawbacks that it occupies a considerably large surface-area, with a length between the finishing stand and the end of the cooling bed, which is comprised within the range of from 75 to about 160 meters, of implying a considerable burden for sheds, foundations, machines, installed powers and staff, and consequently with extremely high operations and maintenance costs.
Furthermore, rolling mills are known in which the bars, sheared to a length multiple of the commercial length by means of a shear installed downstream the finishing stand, are selectively fed to channel-shaped chambers of apparatuses which feed the same bars--while simultaneously cooling them--to the subsequent operating units.
Equipment of this kind is disclosed and illustrated, e.g., in European patent application No. 114,791, filed on Jan. 17th, 1984 to the name of Danieli & C. Officine Meccaniche S.p.A..
Same kind of equipment, although reducing the overall dimensions of the rolling mill, has not been shown to be capable of receiving the bar already sheared to commercial length, in that the required braking cycle would be too long. Furthermore they can process only a limited range of bar diameters.
The general purpose of the present invention is of obviating the above listed drawbacks which can be observed in facilities of the type known from the prior art, by providing a facility for shearing to length rolled bars, which is so conceived, as to occupy a minimal room as compared to the facilities known from the prior art.